RExcel doesn't

RExcel is a commercial product (free for educational use) that is supposed to allow using R from within Excel. The website is here. Unfortunately, it's a pain to install and in the end I couldn't get this to work using R 2.15.3 and Excel 2010. I get the error message "RServer seems to have been disconnected or closed." If you Google this phrase, others have had the same problem.

There are undoubtedly commercial uses for R within Excel, but R has far better programability, better graphics, and better reproducibility. (It's a lot easier to share R code with someone than to share a spreadsheet formula). R can make Excel better, but you shouldn't think that using Excel as a crutch will make it easier to learn R.

RExcel might work, but it also might just waste your time. Even if it works, you'll end up with an Excel/R hybrid that might not work for your colleagues, friends and coworkers, and that has separate licenses distinguishing noncommercial, commercial, and educational uses. (You'll get a headache just trying to figure out the difference between the licenses.)

If you have a business need for RExcel, buy a license (approximately $450 per computer) and get support. However, if you want to learn R, learn R. Don't worry about Excel integration. Excel is platform-dependent and clumsy to work with if you're doing anything non-trivial. If you need to pass data back and forth between R and Excel, use CSV files. It's an old technology, but at least it works.